The present invention relates to a constant flow valve which provides a predetermined uniform flow rate at the secondary side even when changes in pressure differential occur between the primary and secondary sides.
A conventional constant flow valve, such as disclosed in U.S. Pat. No. 3,837,362 is characterized in that changes in the pressure of a fluid flowing into a conduit or a pipe cause a conical head to move against the force of a spring, which results in the automatic control of the effective orifice area between the conical head and the inner surface's contour of a flow restrictor to maintain constant the flow rate on the secondary side. However, the inner surface of the flow restrictor, according to the aforementioned U.S. patent, is expressed only as a contoured passageway or contoured profile and no technical clarification on the contour itself, which is most important to the control of the flow rate, has been disclosed therein. Therefore, constant flow valves according to the above U.S. patent can be conceived as only maintaining the flow rate approximately constant when changes in the pressure of a fluid flowing into the valves occur, and such valves cannot be expected to maintain the flow rate accurately constant.
Accordingly, an object of the present invention is to overcome the disadvantages of such prior art valves and provide a constant flow valve which maintains the flow rate on the secondary side accurately constant even when changes in the pressure differential between the primary and secondary sides occur, such being achieved by providing a contoured profile on the inner surface of the flow restrictor.
Other features which are considered characteristic of the invention are set forth in the appended claims.
Although the invention is illustrated and described in relationship to specific embodiments, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.